Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Peel and chop the carrots and parsnips into uniform 1-inch chunks to ensure even cooking.
Mince the garlic cloves and finely chop the fresh rosemary and thyme leaves.
In a large mixing bowl, combine the chopped vegetables with half of the olive oil, half of the minced garlic, and half of the herbs, salt, and pepper.
Pat the chicken breast dry with a paper towel, then rub with the remaining olive oil, garlic, and herb mixture.
Spread the seasoned vegetables in a single layer on the prepared baking sheet and nestle the chicken breast in the center.
Roast for 25 to 30 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and lightly caramelized.
Let the chicken rest for 5 minutes before slicing to keep the juices intact, then serve alongside the roasted roots.